1. Field of the Invention
This invention relates to a communication apparatus in which transmission power is capable of being changed.
2. Description of the Related Art
A wireless communication unit is so designed as to maximize the transmission power between a master and slave machine in such a manner that the range of transmission capability is made as large as possible. Owing to problems such as intermodulation of radio waves, however, the number of wireless communication units capable of being accommodated by a single system is limited to one or two. Further, in a case where a plurality of wireless communication units are installed, it is required that the locations at which the masters are installed, as well as the locations at which the slaves are installed, be separated from each other in excess of a fixed distance. Thus, there are limiting conditions in terms of use.